However, we think
that this possibility is unlikely to have substantially
affected our results. Although we may not
have captured some cases of venous thromboembolism
that were diagnosed entirely in the
outpatient setting, almost all diagnoses of ischemic
stroke and acute myocardial infarction are
made in the emergency department and result in
hospitalization and our analysis of these
arterial events alone was consistent with our overall
analysis. Furthermore, our estimates of the
magnitude of thrombotic risk within 6 weeks
after delivery closely overlap with those of previous
studies that incorporated detailed clinical
information suggesting that we did not often
miss thrombotic events and incorrectly ascribe
them to later periods.